X-Ray/UVOIR Frequency-resolved Time Lag Analysis of Mrk 335 Reveals Accretion Disk Reprocessing
X-Ray/UVOIR Frequency-resolved Time Lag Analysis of Mrk 335 Reveals Accretion Disk Reprocessing
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DOI：
10.3847/1538-4357/ace77b
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发表时间：
2023-07
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影响因子：
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通讯作者：
Collin Davis Lewin;E. Kara;E. Cackett;D. Wilkins;C. Panagiotou;Javier A. García;J. Gelbord
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文献类型：
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作者：
Collin Davis Lewin;E. Kara;E. Cackett;D. Wilkins;C. Panagiotou;Javier A. García;J. Gelbord
紫外光和光学连续混响作图是探测吸积盘和内宽线区域的有力工具。然而，最近在X射线、紫外线和光学的混响测绘活动中发现，滞后时间始终长于标准光盘再处理图像的预期滞后时间。到目前为止，最大的差异是最近在MRK 335中报告的，其中UV/光学滞后比预期长12倍。在这里，我们使用高斯过程来解释不规则采样，对MRK 335进行频率分辨时滞分析。我们首次将傅里叶频率分辨滞后直接与使用常用的内插互相关函数方法计算的滞后进行了比较，该方法适用于原始和去趋势的光曲线。我们表明，当聚焦于短时间尺度的可变性时，预期的圆盘混响滞后被傅立叶滞后所恢复。这表明，在长时间尺度上存在一个单独的可变性成分。如果这个单独的分量被模拟为来自吸积盘以外另一个区域的混响，我们限制了距离中心黑洞大约15天的大小尺度。这与从Hβ混响滞后中推断的宽线区域的大小是一致的。我们还发现了软X射线滞后的初步证据，我们认为这可能是由于硬X射线日冕和在2keV以下的软X射线光谱中占主导地位的远光电离气体之间的光旅行时间延迟所致。
UV and optical continuum reverberation mapping is a powerful tool for probing the accretion disk and inner broad-line region. However, recent reverberation mapping campaigns in the X-ray, UV, and optical have found lags consistently longer than those expected from the standard disk reprocessing picture. The largest discrepancy to date was recently reported in Mrk 335, where UV/optical lags are up to 12 times longer than expected. Here, we perform a frequency-resolved time lag analysis of Mrk 335, using Gaussian processes to account for irregular sampling. For the first time, we compare the Fourier frequency-resolved lags directly to those computed using the popular interpolated cross-correlation function method applied to both the original and detrended light curves. We show that the anticipated disk reverberation lags are recovered by the Fourier lags when zeroing in on the short-timescale variability. This suggests that a separate variability component is present on long timescales. If this separate component is modeled as reverberation from another region beyond the accretion disk, we constrain a size scale of roughly 15 lt-days from the central black hole. This is consistent with the size of the broad-line region inferred from Hβ reverberation lags. We also find tentative evidence for a soft X-ray lag, which we propose may be due to light travel time delays between the hard X-ray corona and distant photoionized gas that dominates the soft X-ray spectrum below 2 keV.